Plate cylinder with interchangeable plate clamping device

ABSTRACT

Interchangeable sets of printing plate clamping devices for the plate cylinder of letterpress printing machines are provided, one set for clamping lead-backed electrotype plates on the plate cylinder and another set, interchangeable with the first set, for independently clamping plate saddles on the cylinder and thin wraparound printing plates under spring pressure on the saddles. Provision is made for independently clamping two printing plates which are positioned side by side on the plate cylinder.

United States Patent Woessner et a]. 1 Mar. 7, 1972 [54] PLATE CYLINDER WITH 3,230,879 1/1966 Worthington ..101/378 INTERCHANGEABLE PLATE 3,335,663 8/1967 Harenza ....101/415.1 CLAMPING IC 3,359,899 12/1967 Luehrs ....101/4l5.1 3,408,933 11/1968 Hermach et a1. ..101/415.1 2] inventors: Richard Woessner, Fairlawn, -z AleX- 3,410,211 11/1968 Grunig ..101/415.1

ander Z. Benda, Bronx, N.Y. [73] Assignee: Wood Industries, Inc., Plainfield, NJ. FOREIGN PATENTS OR APPLICATIONS 851,841 10/1960 Great Britain ..101/378 [22] May 1968 928,737 6/1963 Great Britain ..101/415.1 21 Appl. No.: 728,185

Primary Examiner-Robert E. Pulfrey Assistant Examiner--Clifford D. Crowder [52] U.S.Cl ..101/378, 101/415.1 511 1111. CL ..1141127/06;, B41f27/10, B41f27/12 Ammekpenme, Edmmds T910 and Adams 58 F'eld (Search ..101 378, 415.1 1 I [57 ABSTRACT [56] Rem'ences Cited Interchangeable sets of printing plate clamping devices for the plate cylinder of letterpress printing machines are provided, UNITED STATES PATENTS one set for clamping lead-backed electrotype plates on the 572,695 12/1896 Cottrell ..101/378 plate cylinder and another set, interchangeable with the first ,875 5/ 1955 Harless ...10l/378 set, for independently clamping plate saddles on the cylinder 5 95 C /3 3 and thin wraparound printing plates under spring pressure on 2,709,406 5/ 1955 Knowles 101/378 h ddl Provision i made for independently clamping two 2,736,259 2/1956 Sather 101/378 printing plates which are positioned side by side on the plate 3,019,729 2/1962 Ringe et al.. 101/378 cylinder 3,126,825 3/1964 Tofano ...101/378 X 3,195,457 7/1965 Luehrs ..101/378 4 Claims, 11 Drawing Figures PATENTEDMAR H972 3.646.886

sum 3 BF 4 A'I'TURNEY PLATE CYLINDER WITH INTERCIIANGEABLE PLATE CLAMPING DEVICE BACKGROUND OFTI-IE INVENTION This invention relates to printing machines in general and to printing plate clamping devices for the plate cylinders of letterpress printing machines in particular.

Printing plate clamping devices of letterpress printing machines, such as, for example, of the magazine printing machine type, are known in the art for clamping the conventional lead-back electrotype plates. An example of this type of clamping device is shown in the Ringe et al. U.S. Pat. No. 3,019,729. The development of thin, flexible sheet metal printing plates, known as wraparound" plates, for letterpress printing, has resulted in the development of plate-clamping devices in plate cylinders for such thin plates, such as shown in the Luehrs U.S. Pat. No. 3,359,899.

However, when a printing machine has been designed and built either for one or for the other type of printing plates, a change from one plate thickness to the other is not readily possible. Conventional plate-mounting saddles do not lend themselves to clamping directly to the thin wraparound plates thereon because the total thickness of the lead-backed electrotype plates is only three-sixteenths to one-fourth inch. Thus, there is the problem of providing for means for clamping the electroplates on the plate cylinder at one time and for clamping relatively thin plate saddles and thin wraparound plates on the plate cylinders at another time without exchanging the plate cylinders.

SUMMARY This invention consists in such novel features, construction arrangements, combinations of parts and improvements as may be shown and described in connection with the device herein disclosed by way of example only and as illustrative of the preferred embodiment. The invention solves the problem as it is set forth in the preceding paragraph for providing interchangeable sets of plate-clamping devices for the plate cylinders, which are adapted for clamping the printing plates of various thicknesses- Objects and advantages of the invention will be set forth in part hereafter and in part will be obvious herefrom or may be learned by practicing the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

It is an object of this invention to provide for contrivances in connection with printing plate cylinders for using printing plates of various thicknesses.

It is another object of the invention to provide for sets of printing plate clamping devices which are interchangeable in the printing plate cylinder.

It is a further object of the invention to provide for plateclamping devices permitting circumferential register setting.

Furthermore, it is an object of the invention to provide for plate-clamping devices for independently locking two plates in side-by-side relationship on the same plate cylinder.

Yet another object of the invention is to provide for clamping devices for printing plates of various thicknesses which are interchangeable on the plate cylinder without removing or altering of the plate cylinder itself.

Various further and more specific purposes, features, and advantages will clearly appear from the detailed description given below taken in connection with the accompanying drawings which form part of the specification and illustrate merely by way of example one embodiment of the device of the invention.

BRIEF DESCRIPTION OF THE DRAWING In the following description and in the claims, parts will be identified by specific names for convenience, but such names are intended to be as generic in their application to similar parts as the art will permit. Like reference characters denote like parts in the several figures of the drawing, in which FIG. I shows a printing plate cylinder, partly broken away, with plate-clamping devices for electrotype plates;

FIG. 2 is an enlarged axial section partly broken away of the plate-clamping mechanism taken along the line 22 in FIG.

FIG. 3 is a similarly enlarged axial section partly broken away of the plate-clamping mechanism taken along the line 3-3 in FIG. 1;

FIG. 4 is a further enlarged radial section, of the plateclamping mechanism, taken along the line 4-4 in FIG. 1;

FIG. 5 is a similar radial section of the plate'clamping mechanism, taken along the line 55 in FIG. 1;

FIG. 6 is an enlarged radial section of the plate-clamping mechanism for use with thin wraparound plates taken along the line 66 in FIG. 8, showing the clamped saddle and the wraparound plate on top of it;

FIG. 7 is a similar radial section of the plate-clamping mechanism taken along the line 77 in FIG. 8, without one saddle;

FIG. 8 shows the printing plate cylinder of FIG. 1 partly broken away, with the saddle and wraparound plate-clamping mechanisms replacing the electrotype plateclamping devices;

FIG. 9 is an enlarged axial section, partly broken away, of the clamping mechanism, taken along the line 9-9 in FIG. 8;

FIG. 10 is an enlarged axial section, partly broken away of the clamping mechanism, taken along the linel0l0 in FIG. 8; and

FIG. 11 is an enlarged detail of the saddle-clamping mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT A printing plate cylinder ll of a letterpress printing machine, preferably of the magazine type is shown in FIGS. 1 and 8. A plurality of grooves 12 are longitudinally milled in the surface of cylinder 11. There are usually four such grooves, evenly spaced apart on the periphery, and two sets of four grooves each longitudinally of cylinder 11 whereby one set is staggered 45 of the other. Self-contained plate-clamping mechanisms 13 of the underside plate-locking type are inserted in grooves 12, as shown in FIGS. 2,3,4 and 5. The mechanism 13 is basically identical with the underside lockup device disclosed in U.S. Pat. No. 3,019,729 with the exception, that mechanisms 13 are adapted for clamping two plates in lateral relationship to one another in such a way that each one of the plates can be clamped independently from the other. For this purpose, one group of spring-loaded clamps 14 are operated by the slider crank mechanism 15, disclosed in the U.S. patent mentioned above, whereas the other group of spring-loaded clamps 16 is operated independently by the slider crank mechanism 17 by way of a sliding bar 18 to which both slider block 17' and the spring rod 19 of the other group of clamps 16 is fastened, the latter by a block 20, as shown in FIG. 2.

Furthermore, the groups of adjustable clamps 21 and 22 are independently adjustable, as shown in FIGS. 1 and 3. Clamps 21 are circumferentially adjusted for registering of the plates by mechanism also disclosed in the U.S. patent mentioned above, being operated by a pair of bevel gears 23 which are mounted on a slider crank mechanism 24 for a fast release of clamps 21 without disturbing the original register setting. Clamps 22 are adjusted in the same manner by the bevel gear mechanism 25 and slider crank 26 similar to the mechanisms 23,24. However, the bevel gear 25 has a threaded rod 27 which is threaded in a block 28 which is firmly anchored in a slide plate 29. A block 30 is fastened to slide 29 and a rod 31 is attached to block 30, which provides for the movement of the clamp mechanisms of clamps 22.

When it is desired to use thin wraparound plates for certain printing purposes instead of the lead-backed electrotype plates, sets 40 of another type of self-contained plate-clamping mechanisms can be inserted in grooves 12 of plate cylinder 11. Sets 13 and 40 are fully interchangeable in grooves 12 without disassembling the cylinder 11 proper as shown in FIGS. 8,9, and and may be used in different grooves of the same cylinder, if it is desired to print from both wraparound plates and lead-backed electrotype plates on the same web. Each set 40 consists of a body 41 in which four stationary mounted underside lockup clamps 42, 42 are located oprod 46 can be axially moved from one end position to the other end position. Four laterally moved blocks 51, 51 operatingly engaging the four rotatable clamps 43, 43' are slidably located on the bottom plates 52,53,54 which are fastened on the underside of the body 55 of mechanism 40. Each one of blocks 51, 51' has a counterbore 56 in which a compression spring 57 is located. Spring 57 is held in place on rod 46 by a screwnut 58 whereas blocks 50, 51' are located by a screwnut 59 on rod 46 for being moved A bushing 60 is arranged on rod 46 in the area of spring 57 for protecting the surface of rod 46 serving at the same time as a spacer between screw units 58,59. Helical gear teeth 61 are cut at an angle of approximately in the upper part of blocks 51 (51') which mesh with correspondingly cut helical teeth 62 in saddlelocking clamps 43,43 which are rotatably mounted on short shafts. The interaction of helical gear teeth 61 and 62 is selflocking by virtue of the helical angle.

Clamps 42,42 for holding the opposite end of the saddle are fixedly secured in place (FIG. 6).

For clamping the thin wraparound printing plates on saddles 44 a further mechanism is arranged in body 41 of set 40. On the stationary side of the plate, designated also as the plate-registering side, bars 65 are provided, one bar for each plate. Bars 65 have vertically extending edges 66 and a plurality of leaf springs 67, fastened to the inner face of bars 65 by small plates 68 and screws 69, spaced apart from one another, as seen in FIGS. 6 and 8. The leading end of wraparound plate 45 is properly bent and is tucked in between bars 65 and leaf springs 67. Located in bars 65 behind leaf springs 67 are small plungers 70 which are arranged to release the pressure of leaf springs on wraparound plate 45 when bars 65 are moved back for unclamping wraparound plate 45 and for tucking a new plate between bars 65 and springs 67. Bars 65 are attached to blocks 71,72 which have helical teeth 73 on the underside thereof. Helical teeth 73 engage in corresponding helical teeth 74 of blocks 75,75" which are clamped by screwnuts 76 on rods 77,78 which extend axially of cylinder 11 and of insert 40. Rod 77 is anchored in 75' in which a threaded rod 79 is engaged. Rod 79 is rotated by a pair of bevel gears 80,81 which are located in slide 82. By a slider crank mechanism 83, similar to slider crank mechanism 48, slide 82 can be moved in axial direction, pulling block 75 and rod 77 and moving blocks 71 by virtue of helical gear teeth engagement 73, 74 for releasing wraparound plate 45 without disturbing the plate register setting which has been performed by rotating bevel gears 80, 81 moving rod 79 in axial direction independently of the movement of block 82.

Rod 78 is fastened to a block 102 which is anchored on a sliding bar 103. Rod 78 carries the blocks 75" which are secured to rod 78 by screwnuts 76. Blocks 75" engage blocks 72 in the same manner as described above with respect to blocks 75 and 71(Blocks 72 carry a second bar 65' for clamping a wraparound plate 45' which is located on the side of plate 45, as described above. Sliding bar 103 is fastened to a block 104 in which a rod 105 is threadedly engaged. Rod 105 is part of a bevel gear 106 which is in mesh with a bevel gear 107. Bevel gears 106 and 107 are located in the sliding block 108 of a slider crank mechanism 109 which is similar to slider crank mechanism 83. Thus, sliding bar 103 can axially move pulling block 102 and therewith rod 78 for releasing wraparound plate 45 in the same manner, as described with respect to plate 45, without disturbing the register setting which had been performed by bevel gears 106 and 107 and threaded rod 105.

Opposite bars and parallel thereto are clamping bars 85 arranged in body 41, one for each printing plate, extending longitudinally the same length as bars 65. Bars 85 have radially extending edges 86 similar to edges 66 and have also a plurality of leaf springs 87, spaced apart from one another, fastened to bars 85 by small plates 88 and screws 89. Small plungers 90 are located in bars 85 behind leaf springs 87 for releasing the pressure between bars 85 and leaf springs 87 when bars 85 are retracted for inserting the bent edge of a new wraparound plate 45 or for unclamping a used one. Guide pins 91 are provided in body 41, engaging in corresponding bores 92 of bars 85. Bars 85 are attached to a plurality of blocks 93 which are slidably arranged in body 41 for moving bars 85 in a direction which is perpendicular to the longitudinally extending bars 85. Each one of blocks 93 has helical teeth 94 on the underside thereof, engaging the helical teeth 95 of one of the plurality of the longitudinally moving blocks 96. A disc-type compression spring 97 is located behind each one of blocks 93 whereby bars 85 carried by blocks 93 clamp wraparound plate 45 tightly onto saddle 44 (FIG. 6.). Blocks 96 slide freely on bottom plates 53, 54. A sliding bar 98 extends longitudinally underneath blocks 96 and 51,51. Small lugs 99 are firmly attached to bar 98 for moving blocks 96 in one direction (FIG. 7) and permitting blocks 96 to slide back freely when bar 98 is moved in the opposite direction. in order to permit blocks 96 to slide back under the force of springs 97, the angle of inclination of helical teeth 93, 94 is such that the interaction of the helical teeth is not self-locking.

A slider crank mechanism 100 is arranged in line with sliding bar 98, and the slider block 101 of slider crank mechanism 100 is fastened on sliding bar 98. By operating slider crank mechanism 100 the lugs 99 move blocks 96 in unison, moving the blocks 93 against disc springs 97 and thus retracting bars 85 and releasing the wraparound printing plate 45.

OPERATION it has been specified above that the self-contained devices for clamping the electrotype printing plates can be exchanged for the devices for clamping of the thin wraparound plates and for independently clamping of the saddles for the wraparound plates. When the latter devices have been fastened in the grooves of the plate cylinder, the saddles for mounting of the wraparound plates are clamped first. There are four saddles on the circumference of the cylinder and two saddles side by side per one-half of the total length of the plate cylinder. The two saddles which are arranged side by side are clamped simultaneously by the mechanism as shown in FIGS. 6, 8, and 9. The saddles are hooked on the stationary clamps 42, and by turning the key in the slider crank mechanism 48, rod 46 is pulled in the axial direction whereby all springs 57 are compressed, which in turn moves blocks 51, 51' in the same direction. The rotatable clamps 43 thereby are forced to en gage the grooves in the saddles 44, clamping them firmly on the surface of the cylinder. Since the helical teeth 61 of blocks 51, 51 and the teeth 62 of the rotatable clamp are arranged at a self-locking angle, the clamps cannot become unlocked.

The wraparound printing plates, usually 0.032 inch thick, are now placed on top of the saddles (usually about one-fourth inch thick). Each one of these plates can be clamped individualiy so that each one can be set to proper page and color register, and can be exchanged, as the case may be, without disturbing the setting of the adjacent plate. The longitudinal edges of the plates have been prepared in advance by bending to an acute angle, as indicated. The clamping bars 65 and for the wraparound plateare retracted so that the bent edges of the plate can beinserted between the leaf springs 67, 86 and the bars 65 and 85. The plunger 70 and deflect the leaf springs enough so that the bent ends can be easily inserted. By

operating the slider crank mechanism 83 and 109 the bars 65 are moved forward into the operating position through the intermediate of rods 77, 78, blocks 75, 75" and sliding plate 103. In this position the circumferential registering operation can be performed by turning the screw shafts 79 and 105, respectively, through the bevel gears 80, 81 and 106 and 107 respectively. When the register has been adjusted, the wraparound plates can now be clamped by the bars 85 by operating the slider crank mechanism 100, whereby the axial movement of the sliding plate 98 is performed, This movement releases the locking of the blocks 93 which carry the clamping bars 85, so that the disc springs 97 can force the blocks 93 and clamping bars 85 with their clamping edges 86 in the forward direction whereby the wraparound plate 45 is firmly clamped on the saddle 44 under the holding force of the springs 97.

While the invention has been described and illustrated with respect to a certain preferred example which gives satisfactory results, it will be understood by the skilled in the art after understanding the principle of the invention, that various other changes and modifications may be made without departing from the spirit and scope of the invention and it is intended therefor in the appended claims to cover all such changes and modifications What is claimed is:

1. Plate-clamping mechanism for mounting printing plates of different thicknesses onto the plate cylinder of a rotary printing machine of the magazine printing type, comprising in combination a plurality of substantially shallow grooves extending longitudinally over the surface of said plate cylinder, a first and a second set of clamping inserts interchangeable in said grooves with each said set of clamping inserts disposed for holding two printing plates on said cylinder in side-by-side relationship, the said first set having first clamping means thereon for clamping the underside of thin lead-backed electroplates onto said cylinder, and the said second set having second clamping means thereon for clamping the underside of plate saddles onto said plate cylinder and having holding means thereon for holding thin flexible wraparound printing plates onto said saddle where said holding means is operable independently of said second clamping means and said holding means has circumferentially adjustable registry means which is adjustable independently of the said second clamping means.

2. Plate-clamping mechanism according to claim 1 wherein said holding means further comprises spring-loaded plateclamping bars and a plurality of leaf spring blades on each said clamping bar, said leaf springs holding the longitudinal edges of said thin flexible wraparound printing plate on said bars.

3. Plate-clamping mechanism according to claim 2 having in addition a plurality of plungers slidably located in said clamping bars, said plungers adapted to release said leaf springs form a position holding the edges of said thin flexible wraparound printing plates upon retracting of said clamping bars.

4. Plate-clamping mechanism for mounting a thin flexible wraparound printing plate onto the plate cylinder of a rotary printing machine of the magazine printing type, comprising in combination a plurality of substantially shallow grooves extending longitudinally over the surface of said plate cylinder, a set of clamping inserts in said grooves disposed for holding two printing plates in side-by-side relationship on said cylinder, said set having clamping means thereon to clamp the underside of a plate saddle onto said plate cylinder and in addition holding means thereon for holding a thin flexible wraparound printing plate onto said saddle wherein said holding means is operable independently of said clamping means and wherein said holding means has circumferentially adjustable registry means which is adjustable independently of said clamping means whereby the thin printing plate may be ad- 

1. Plate-clamping mechanism for mounting printing plates of different thicknesses onto the plate cylinder of a rotary printing machine of the magazine printing type, comprising in combination a plurality of substantially shallow grooves extending longitudinally over the surface of said plate cylinder, a first and a second set of clamping inserts interchangeable in said grooves with each said set of clamping inserts disposed for holding two printing plates on said cylinder in side-by-side relationship, the said first set having first clamping means thereon for clamping the underside of thin lead-backed electroplates onto said cylinder, and the said second set having second clamping means thereon for clamping the underside of plate saddles onto said plate cylinder and having holding means thereon for holding thin flexible wraparound printing plates onto said saddle where said holding means is operable independently of said second clamping means and said holding means has circumferentially adjustable registry means which is adjustable independently of the said second clamping means.
 2. Plate-clamping mechanism according to claim 1 wherein said holding means further comprises spring-loaded plate-clamping bars and a plurality of leaf spring blades on each said clamping bar, said leaf springs holding the longitudinal edges of said thin flexible wraparound printing plate on said bars.
 3. Plate-clamping mechanism according to claim 2 having in addition a plurality of plungers slidably located in said clamping bars, said plungers adapted to release said leaf springs form a position holding the edges of said thin flexible wraparound printing plates upon retracting of said clamping bars.
 4. Plate-clamping mechanism for mounting a thin flexible wraparound printing plate onto the plate cylinder of a rotary printing machine of the magazine printing type, comprising in combination a plurality of substantially shallow grooves extending longitudinally over the surface of said plate cylinder, a set of clamping inserts in said grooves disposed for holding two printing plates in side-by-side relationship on said cylinder, said set having clamping means thereon to clamp the underside of a plate saddle onto said plate cylinder and in addition holding means thereon for holding a thin flexible wraparound printing plate onto said saddle wherein said holding means is operable independently of said clamping means and wherein said holding means has circumferentially adjustable registry means which is adjustable independently of said clamping means whereby the thin printing plate may be adjusted circumferentially with respect to said saddle. 